从热工学角度探讨国产吸收式制冷机的发展方向

该文从热工学角度探讨了目前我国溴化锂吸收式制冷机整机热力循环及各热质交换设备性能、结构等方面存在的问题;在整机循环方面,指出实现各设备的合匹配、发展新的结构流程及增加新品种、新规格的机组为进一步的发展方向;在各设备性能、结构方面提出应加强吸收机理研究以及表面活化剂、高效强化管的应用研究。     

塑料管单效溴化锂吸收式制冷机理论研究

分析了塑料管单效溴化锂吸收式制冷机的理论循环，对塑料管单效溴化锂吸收式制冷机进行了热力计算和传热计算，为塑料管单效溴化锂吸收式制冷机的结构设计及实验研究提供理论依据。     

混合工质脉管制冷机性能的数值模拟

开发了适用于混合工质的脉管制冷机的计算程序，利用此程序对应用混合工质提高脉管制冷机的制冷性能进行了研究，发现当混合工质采用氦气和氢气，且处于合适的配比下，可以进一步改进脉管制冷机的制冷性能，给出了当混合工质最佳配比时，脉管制冷机内热力参数的瞬时变化及一周期的循环参数，用该计算程序可以获得混合工质脉管制冷机内复杂过程的详细信息，为制冷机设计和改进提供依据。     

有限热源吸收式制冷机的热力学建模与分析

考虑了有限热容、有限速率传热以及工质内部耗散的影响,建立了吸收式制冷机的热力学模型.在该模型中,吸收式制冷机被等价为一个不可逆卡诺热机驱动不可逆卡诺制冷机的联合循环系统.为描述循环的内不可逆性,引入了两个内不可逆性参数Ihe和Ir.其中,Ihe用于描述热机循环的内不可逆性,Ir用于描述制冷循环的内不可逆性.通过对给定供热率下热机热效率和给定制冷率下两热源制冷机性能系数解析表达式的推导,并根据等价系统的定义,获得了吸收式制冷机给定制冷率下性能系数的解析表达式,利用该表达式详细地分析了各参数对性能系数的影响.所得公式和分析结论对实际系统的理解、设计以及分析具有一定的理论指导作用.     

自然循环热水锅炉进水装置的优化设计

在热水锅炉的优化设计中，要保证上升管、下降管水流速，增加循环动力压头，以保证锅炉安全运行，提高锅炉寿命，通过对引射和插入两种装置的分析计算，总结出在不改变锅炉结构的情况下，增加循环动力压头的方法。     

热管废热溴化锂制冷机的优化设计

介绍了烟气驱动的热管废热溴化锂制冷机的优化设计，建立了热管废热溴化锂制冷机的优化设计计算模型，并编写了优化设计程序，得出了整个装置的结构参数。     

氨水吸收式制冷系统在渔船尾气中余热利用分析

渔船出海作业时,需携带冰块为渔产品保鲜,而100 t以下的中小型渔船因经济性的限制.不宜安装压缩式制冷机.文中介绍了一种渔船利用自身动力柴油机的尾气驱动氨水吸收式制冷机的技术,该技术采用可提高循环效率的溶液冷却吸收和溶液加热发生的循环方式,计算表明该改进型循环比传统循环的COP提高20%左右.     

内可逆四热源吸收式制冷循环的热经济性能优化

应用内可逆四热源吸收式制冷循环模型，分析吸收式制冷机受传热不可逆性影响时的热经济性能。在牛顿传热定律下，导出了循环的最佳热经济性目标和制冷系数的基本优化关系和最大热经济性目标及相应的制冷系数与比制冷率；通过数值算例，得出循环参数对循环的热经济性目标、制冷系数和比制冷率的影响关系。     

溴化锂制冷机的化学清洗方法

为了冷却工厂的工艺用水使其循环使用，采用双效溴化锂吸收式制冷机组是一个较好的方案，但也出现了易结垢等问题。作者介绍了制冷机的化学清洗方法、操作规程及监测指标。     

能源、环保文献消息(国外部分)

InformationofEnergyandEnvironmentalProtection（AbroadPart）992001制冷机的操作与维修EnergyEngineeringVol.1No．11997p69-79本文主要探讨了制冷机的操作与维修，包括吸收式制冷循环、保持真空度、维修安排、控制内部腐蚀速率和排除不凝性气体。992002控制换气事还是空气过滤？用气用空气过滤达到ASHRAE62标准EnergyEngineeringVol.94No．31997p6-31将室内排出空气经气相空气过滤系统净化后循环使用，可减少室外空气的吸入量，从而降低能耗。本文着重介绍了后一种方案和几个成功应用的实例。992003管道保温的成本效益分析Ener…     

An indirect evaporative chiller

A novel indirect evaporative chiller driven by outdoor dry air to produce cold water as the cooling source for air conditioning systems is introduced, and the principle and the structure of the chiller is presented. The cold water can be produced almost reversibly under ideal working conditions, with its temperature infinitely close to the dew point temperature of the inlet air. The key components of the chiller are an air cooler and a padding tower. To improve the heat transfer performance inside the chiller, a quasi-countercurrent air cooler was designed; a subsection linear method was used for the mathematical model of the padding tower. The first indirect evaporative chiller, designed and developed in 2005, has been in use in Kairui Building, a big hotel in Shihezi, Xinjiang Autonomous Region. The tested temperature of the water produced is below the wet bulb temperature of outdoor air and reached the average value of the dew point temperature and the wet bulb temperature of outdoor air. As the running components are only pumps and fans, the COP (cooling energy for room divided by power cost) of this chiller is high, and the drier the outdoor air, the higher COP the chiller obtained. Since no CFCs are used in this chiller, it would not cause any pollution to the aerosphere. Finally, the application prospect of the indirect evaporative chiller in the world is presented.     

Study on a silica gel–water adsorption chiller integrated with a closed wet cooling tower

A silica gel–water adsorption chiller integrated with a closed wet cooling tower is proposed. This adsorption chiller consists of two vacuum chambers, each with one adsorber, one condenser and one evaporator. Vacuum valves were not adopted in this chiller in order to enhance the reliability. A novel heat recovery process was carried out after a mass recovery-like process to improve the coefficient of performance (COP). Integration of the closed wet cooling tower into the chiller could ensure the cleanliness of cooling water circulating in the chiller and also promote the convenient setup of the chiller. A transient one-dimensional mathematical model was adopted to study this adsorption chiller. The simulated results showed that the cooling power and COP were 10.76 kW and 0.51 respectively when the hot water inlet temperature, the chilled water inlet temperature, the air inlet wet bulb temperature and dry bulb temperature were 85, 15, 28 and 30 °C respectively.     

Simulation of operating characteristics of the silica gel-water adsorption chiller powered by solar energy

A lumped parameter model of a silica gel-water adsorption chiller driven by solar energy was introduced for the operating characteristics investigation. Matlab-Simulink, as a high-performance computing and programming tool, was used to simulate the operating characteristics of the chiller. Effects of the hot water tank capacity, the cycle time and the initial hot water temperature on the performance of the chiller were analyzed when the chiller was driven by a stable heat source and solar energy respectively. The simulation results indicated that when the chiller was driven by solar energy, the open circulation of the hot water with a short cycle time and the closed circulation of hot water with a longer cycle time were better. A proposal was also provided for the chiller driven by solar energy to work under the optimum working conditions, such as hot water circulation mode, cycle time and initial temperature.     

Experimental study on improved two-bed silica gel–water adsorption chiller

A novel silica gel–water adsorption chiller with two chambers has been built in Shanghai Jiao Tong University (SJTU). This chiller combines two single bed systems (basic system) without any vacuum valves. One adsorber, one condenser and one evaporator are housed in the same chamber to constitute one adsorption/desorption unit. In this work, the chiller is developed and improved. The improved chiller is composed of three vacuum chambers: two adsorption/desorption vacuum chambers (the same structure as the former chiller) and one heat pipe working vacuum chamber. The evaporators of these two adsorption/desorption units are combined by a heat pipe. So, no valves are installed in the chilled water sub system and one vacuum valve connects the two adsorption/desorption chambers together to improve its performance. The performance of the chiller is tested. As the results, the refrigerating capacity and the COP of the chiller are, respectively, 8.69 kW and 0.388 for the heat source temperature of 82.5 °C, the cooling water temperature of 30.4 °C and the chilled water outlet temperature of 11.9 °C. For a chilled water outlet temperature of 16.5 °C, the COP reaches 0.432, while the refrigerating capacity is near 11 kW. There is an improvement of at least 12% for the COP compared with the former chillers.     

Performance modelling of air-cooled twin-circuit screw chiller

A large variety of chiller models are available in the public domain but none can model chillers that comprise multiple and separate refrigerant circuits, despite that chillers of this type are already widely used for their good part-load performance. Presented in the paper is a mathematical model for an air-cooled twin-circuit chiller, with two screw compressors per circuit. The chiller model comprises a series of linked mathematical modules, each made up of a set of thermodynamic and empirical equations for modelling the major chiller components. The coefficients in the component models were evaluated using rated operating conditions obtained from the manufacturer and measured performance data of an existing chiller. The chiller model had been applied to simulate the performance of another set of chiller of the same make and model. Comparison of the predicted and measured performance of the chiller showed that the model could yield accurate energy use predictions over a wide range of operating conditions. The model could also provide good predictions of the variation in chiller performance due to staged operation of the separate refrigerant circuits in the chiller and of compressors in each circuit, which matched with observations made with measured chiller operation data.     

Theoretical and testing performance of an innovative indirect evaporative chiller

An indirect evaporative chiller is a device used to produce chilled water at a temperature between the wet bulb temperature and dew point of the outdoor air, which can be used in building HVAC systems. This article presents a theoretical analysis and practical performance of an innovative indirect evaporative chiller. First, the process of the indirect evaporative chiller is introduced; then, the matching characteristics of the process are presented and analyzed. It can be shown that the process that produces cold water by using dry air is a nearly-reversible process, so the ideal produced chilled water temperature of the indirect evaporative chiller can be set close to the dew point temperature of the chiller’s inlet air. After the indirect evaporative chiller was designed, simulations were done to analyze the output water temperature, the cooling efficiency relative to the inlet dew point temperature, and the COP that the chiller can performance. The first installation of the indirect evaporative chiller of this kind has been run for 5 years in a building in the city of Shihezi. The tested output water temperature of the chiller is around 14–20 °C, which is just in between of the outdoor wet bulb temperature and dew point. The tested COP_r,s of the developed indirect evaporative chiller reaches 9.1. Compared with ordinary air conditioning systems, the indirect evaporative chiller can save more than 40% in energy consumption due to the fact that the only energy consumed is from pumps and fans. An added bonus is that the indirect evaporative chiller uses no CFCs that pollute to the aerosphere. The tested internal parameters, such as the water–air flow rate ratio and heat transfer area for each heat transfer process inside the chiller, were analyzed and compared with designed values. The tested indoor air conditions, with a room temperature of 23–27 °C and relative humidity of 50–70%, proved that the developed practical indirect evaporative chiller successfully satisfy the indoor air conditioning load for the demo building. The indirect evaporative chiller has a potentially wide application in dry regions, especially for large scale commercial buildings. Finally, this paper presented the geographic regions suitable for the technology worldwide.     

Development and comparison of two-bed silica gel–water adsorption chillers driven by low-grade heat source

A novel silica gel–water adsorption chiller (driven by hot water of 60–90 °C) with three vacuum chambers has been built in Shanghai Jiao Tong University (SJTU). This chiller was an improvement of an earlier deigned chiller and it integrated two single-bed systems (basic system) with only one vacuum valve. The performance of the chiller was tested and compared with the former adsorption chiller. The results show that the cooling power and COP of the chiller are 8.70 kW and 0.39 for the heat source temperature of 82.5 °C, cooling water temperature of 30.4 °C and chilled water outlet temperature of 12 °C. For a higher chilled water outlet temperature of about 16 °C, the COP increases to 0.43 while the cooling power is about 11.0 kW. Compared with that of the former chiller, the COP of this chiller increases by 20%.     

溴化锂吸收式制冷机采用塑料传热管的研究

提出了在溴化锂吸收式制冷机中采用塑料传热管代替铜传热管,以解决传热管腐蚀及其引起的冷量衰减问题。以1台制冷量为35kW的溴冷机为例,对采用塑料传热管的溴冷机与传统铜管溴冷机相关部件的参数进行比较。通过对溴冷机的传热面积、管道阻力的计算和安全强度的校核,发现采用塑料传热管的溴冷机在技术上是可行的。     

Study of a novel solar adsorption cooling system and a solar absorption cooling system with new CPC collectors

One two-phase thermo-syphon silica gel-water solar adsorption chiller and LiBr-H₂O absorption chiller with new medium CPC (Compound Parabolic Concentrator) solar collectors were investigated. The reliability of adsorption chiller can be improved, because there is only one vacuum valve in this innovative design. Medium temperature evacuated-tube CPC solar collectors were firstly utilized in the LiBr-H₂O air conditioning system. The former system was applied in north of China at Latitude 37.45° (Dezhou city, China), the latter system was applied at Latitude 36.65° (Jinan city, China). Experimental results showed that the adsorption chiller can be powered by 55 °C of hot water. The adsorption chiller can provide 15 °C of chilled water from 9:30 to 17:00, the average solar COP (COPs) of the system is 0.16. In the absorption cooling system, the efficiency of the medium temperature evacuated-tube CPC solar collector can reach 0.5 when the hot water temperature is 125 °C. The absorption chiller can provide 15 °C of chilled water from 11:00 to 15:30, and the average solar COPs of absorption system is 0.19.     

Physical and operating conditions effects on silica gel/water adsorption chiller performance

Adsorption refrigeration systems are commercially developed due to the need of replacing the conventional systems which utilise environmentally harmful refrigerants and consume high grade electrical power. This paper presents the key equations necessary for developing a novel empirical lumped analytical simulation model for commercial 450 kW two-bed silica gel/water adsorption chiller incorporating mass and heat recovery schemes. The adsorption chiller governing equations were solved using MATLAB® platform integrated with REFPROP® to determine the working fluids thermo-physical properties. The simulation model predicted the chiller performance within acceptable tolerance and hence it was used as an evaluation and optimisation tool. The simulation model was used for investigating the effect of changing fin spacing on chiller performance where changing fin spacing from its design value to minimum permissible value increased chiller cooling capacity by 3.0% but decreased the COP by 2.3%. Furthermore, the effect of generation temperature lift on chiller performance and the feasibility of using it as a load control tool will be discussed. Genetic Algorithm optimisation tool was used to determine the optimum cycle time corresponding to maximum cooling capacity, where using the new cycle time increased the chiller cooling capacity by 8.3%.